At the present time, asphalt paving material generally surrounds manholes and catch basins. However, optimum compaction of the asphalt adjacent the periphery of the manhole or catch basin leads to deterioration of the asphalt in use. Expansion and contraction of the pavement occurs with varying temperature and leads to asphalt break-up, cracking and separation between pavement and manhole. Repairs typically are required at least every two to three years.
A search of the prior art conducted in the U.S. Patent and Trademark Office has located the following U.S. patents as the most relevant prior art:
______________________________________ 3,263,580 4,808,025 4,927,290 5,030,030 4,759,656 4,925,336 4,969,771 FR2303122 ______________________________________
With respect to the prior art, U.S. Pat. Nos. 5,030,030 and 4,925,336 contain the same disclosure. These references describe a pad which supports a utility access conduit in a roadway. The support pad comprises a rectangular block of rubber or similar compressibly resilient elastomeric material which has an opening through it to snugly engage the access conduit.
U.S. Pat. No. 3,263,580 discloses a safety cover for a manhole which overlies the manhole cover, sits flush with a roadway and is fastened to the manhole cover by bolts. The cover also surrounds the upper portion of the manhole structure at the periphery.
French Patent No. 2,030,122 describes a procedure for fixing the frame of a manhole cover in place. A ring-shaped rebate is formed surrounding the frame and a sealant comprising a hardenable resin material is passed into the rebate and hardened to provide the final structure.
It will be apparent from the discussion below that none of this prior art discloses or suggests the structures which are described herein.